docs: def performance_view(dstore):
      """
      Returns the performance view as a numpy array.
      """
      data = sorted(dstore['performance_data'], key=operator.itemgetter(0))
      out = []
      for operation, group in itertools.groupby(data, operator.itemgetter(0)):
          counts = 0
          time = 0
          mem = 0
          for _operation, time_sec, memory_mb, counts_ in group:
              counts += counts_
              time += time_sec
              mem = max(mem, memory_mb)
          out.append((operation, time, mem, counts))
      out.sort(key=operator.itemgetter(1), reverse=True)  # sort by time
      return numpy.array(out, perf_dt)